1. Field of the Invention
This invention relates to a medium feeder.
2. Description of Related Art
A conventional information processing apparatus such as a printer, a photocopier, a facsimile machine, a multifunctional apparatus, for example, a conventional printer is installed with a paper feeder serving as a medium feeding apparatus to feed a paper as a medium as well as a sheet member. The paper feeder is to be installed with a paper separator which enables the paper feeder to feed the papers upon separating sheet by sheet.
FIG. 2 is a schematic view of a conventional paper feeder.
As shown in FIG. 2, a separating pad 16 is pressed against a feeding roller 11 by a predetermined pressing force to sandwich a paper 12 between the feeding roller 11 and the separating pad 16. Each frictional force between the papers 12 is lower than each of frictional forces between the paper 12 and the feeding roller 11, and between the paper 12 and the separating pad 16, so that the paper 12 in contact with the feeding roller 11 is conveyed with the feeding roller 11 in association with rotation of the feeding roller 11 in a direction of arrow a, thereby being separated from the other papers 12 remaining under a frictional force of the separating pad 16.
Numeral 13 is a paper tray; numeral 14 is a receiving plate; numeral 15 is a paper sensor; numeral 17 is a separating pad frame; numeral 18 is a spring; and numeral 22 is a guide.
In the meanwhile, such a pressing force of the separating pad 16 as capable of separating the paper 12 without problems differs depending on a condition of the paper 12, such as a type, a thickness, a size, a usage environment, and the like.
Therefore, such a paper feeder has been provided, as feeding the paper upon varying a pressing force of the separating pad 16 according to a type of the paper previously input into the printer (see, e.g., Japanese Patent Laid-Open No. 2001-180835).
The conventional paper feeder described above, however, cannot necessarily feed the paper smoothly in a case where the a feeding unit composed of a regist roller, not shown, and the like is disposed at a downstream side of the feeding roller 11 in a direction of conveying the paper 12. For example, in a case of using a thin paper, the paper undesirably gets wrinkled where a pressing force of the separating pad 16 is increased.
This invention aims to solve the above described problems in the conventional paper feeder and to provide a medium feeding apparatus capable of feeding a sheet member smoothly.